This watch is Bluetooth 3.0. All functions support android 4.3 and up smart phones. But for iphone, it just support answer & call, phone book, music play, camera, clock, pedometer, phone anti-lost alert. Still not support SMS, Radio, remote camera control, sleep monitoring, etc. Pls Make Sure your SIM card is Post-paid SIM card, and it Support 2G Network: GSM 850/900/1800/1900MHz